Power operated fastener driving devices are in widespread use in the construction and building trades and typically include a power operated driving mechanism mounted within a housing that powers the driving movement of a drive element slidably mounted within a drive track that extends through a nose piece mounted to the housing. Typically when the driving mechanism is actuated, the drive element moves in a fastener driving direction through a drive stroke and then moves in the opposite direction through a return stroke during one cycle of operation. A trigger mechanism that is movable through an actuation stroke is commonly provided on the exterior of the housing to initiate an operating cycle.
A magazine assembly mounted to the housing supplies a series of fasteners to the drive track through a lateral opening in the same and the leading fastener in the drive track is driven outwardly of the drive track into a workpiece by the driving movement of the drive element when the driving mechanism is actuated. Typically a spring biased fastener feeding device advances the fasteners through the magazine toward and into the drive track.
Power operated fastener driving devices typically include a trip assembly mounted on the nosepiece and operatively associated with the trigger mechanism to prevent the driving mechanism from being actuated when the nosepiece is not in contact with a workpiece.
Often the trip assemblies of fastener driving devices include adjustable mechanisms that can be adjusted manually to control the depth to which a fastener is driven into the workpiece. A safety trip assembly including a manual adjustment mechanism is disclosed in U.S. Pat. No. 6,209,770.
Referring to FIG. 12, a workpiece engaging portion 64A of the safety trip assembly 60A according to the prior art has a distal end 78A, a proximal end 88A, and a fixed locking structure 70A between the ends 78A and 88A. A movable locking member 74A releasably engages the fixed locking structure 70A to retain the workpiece engaging portion at a desired position of extension. A retaining projection 89A is integrally cast on the workpiece engaging portion 64A near the distal end 88A. The retaining projection 89A engages the movable locking member 74A at a fully extended position of the workpiece engaging portion 64A to define a maximum longitudinal length of the safety trip assembly 60A (as defined by the position of the workpiece engaging portion 64A). The safety trip assembly 60A is biased toward and into an extended position by a spring 101A. The retaining projection 89A prevents removal of the workpiece engaging portion 64A from the safety trip assembly 60A. The retaining projection 89A also prevents the workpiece engaging portion 64A from falling or dropping out of the safety trip assembly if the movable locking member 74A is depressed so that it is released from locking engagement relation with the fixed locking structure 70A and held in such relation while the fastener driving tool is in a position with the nosepiece assembly facing down. As a result, heretofore the movable workpiece engaging portion of the prior art discussed above is a permanent part of the safety trip assembly.
While the prior art described above has worked extremely well for its intended use, more recently a need has developed for a more flexible and modular tool.
The present invention provides a safety trip assembly that includes a workpiece engaging portion that can be moved in the longitudinal direction of the safety trip assembly to adjust the longitudinal length of the safety trip assembly and also to remove the workpiece engaging portion from the safety trip assembly for exchanging the workpiece engaging portion with another workpiece engaging member.
According to one aspect of the invention, a fastener driving tool for driving fasteners into a workpiece includes a housing assembly including a nosepiece assembly defining a longitudinally-extending fastener drive track. A fastener driving mechanism is carried internally of the housing assembly and constructed and arranged to drive a fastener through the fastener drive track and into a workpiece when the fastener drive mechanism is selectively activated by a user. A manually actuatable trigger mechanism is constructed and arranged to activate the fastener driving mechanism when manually actuated by a user.
A safety trip assembly includes a trigger enabling portion and a workpiece engaging portion slidably mounted to the trigger enabling portion for rectilinear sliding movement in a longitudinal direction relative to the trigger enabling portion. A manually operable locking mechanism includes a manually-operable, movable locking member mounted to the trigger enabling portion for movement between a locking position and a releasing position, the movable locking member in the locking position thereof engaging the workpiece engaging portion to releasably couple the workpiece engaging portion to the trigger enabling portion and thereby fix a longitudinal length of the safety trip assembly, the movable locking member in the releasing position thereof being disengaged from the workpiece engaging portion to enable the workpiece engaging portion to be slid rectilinearly in the longitudinal direction relative to the trigger enabling portion for adjusting the longitudinal length of the safety trip assembly and for removing the workpiece engaging portion from the safety trip assembly.
A spring biases the movable locking member into the locking position, the spring permitting the movable locking member to be manually moved to the releasing position against the biasing force by a user""s hand engaging the movable locking member to move the movable locking member from the locking position to the releasing position and to automatically return to the locking position when the movable locking member is disengaged by the user""s hand.
According to another aspect of the invention, the workpiece engaging portion is removable from the safety trip assembly. A workpiece engaging portion according to this aspect of the invention includes a positioning mechanism having an opening locating structure and a guiding structure. The opening locating structure is movably connected to the safety trip assembly and is adapted to extend into the opening to align the nosepiece assembly with respect to the opening. The opening locating structure is movable relative to the safety trip assembly between an extended position by a first biasing spring to facilitate locating of the opening, and movable to a retracted position when the opening locating structure is pressed against the workpiece. The guiding structure is movably connected to the nosepiece assembly and is biased by a second spring to extend forwardly to guide the fastener in the drive track.
In accordance with another aspect of the invention, a method is provided for exchanging different workpiece engaging portions of a safety trip assembly in a fastener driving tool for driving fasteners into a workpiece, the safety trip assembly including a trigger enabling portion and a workpiece engaging portion, the workpiece engaging portion slidably mounted to the trigger enabling portion for movement in a longitudinal direction relative to the trigger enabling portion, the safety trip assembly being movable when the workpiece engaging portion is releasably coupled to the trigger enabling portion between an extended position and a retracted position whereby the trigger enabling portion enables the trigger mechanism to activate the fastener driving mechanism when manually actuated by a user when the safety trip assembly is in the retracted position and disables the trigger mechanism when the safety trip assembly is not in the retracted position.
The method includes manually engaging and moving a manually-operable, movable locking member mounted to the trigger enabling portion against a biasing of a spring from a locking position wherein the locking member lockingly engages a first workpiece engaging portion to releasably couple the first workpiece engaging portion to the trigger enabling portion to a releasing position wherein the locking member is disengaged from the first workpiece engaging portion. While the locking member is in the releasing position thereof, the first workpiece engaging portion is moved relative to the trigger enabling portion until the first workpiece engaging portion is removed from the safety trip assembly, and a second workpiece engaging portion different from the first workpiece engaging portion is moved relative to the trigger enabling portion so that the second workpiece engaging portion is mounted to the trigger enabling portion. The locking member is manually released to allow the spring to bias the movable locking member from the releasing position back into the locking position to thereby lockingly engage the second workpiece engaging portion.
Other aspects of the invention will be appreciated from the following description and appended claims.